The families of men killed in New Zealand's Pike River mine disaster say they feel betrayed by a decision to delay the recovery of bodies until the mine is operational again.

The country's largest coal miner, Solid Energy, has agreed to pay $7.5 million for the mine and to pay another $25 million after coal extraction resumes.

But the company says it will be years before the bodies of the those killed in the 2010 explosion can be recovered, if it is ever possible.

A series of underground explosions at the west coast mine in November 2010, killed 29 men, including two Australians.

Since then, work has been underway to stabilise the mine so that the bodies can be recovered.

Solid Energy's chief executive officer Don Eldernow says the company will only attempt a recovery operation if a new commercial mine can be built.

"It may well turn out to be we spend a lot more doing drilling over the next few years and in the end we say that was money that we're going to have to write off," he said.

Prime minister John Key has always said that he is committed to financially assisting a recovery operation and he's been called a liar and everything by the opposition now that this recovery plan looks like it's been put on hold yet again.

But John Key says that he remains committed to assisting any recovery but that it has to be a safe and viable one. So again it comes back to Solid Energy having a plan which they think is going to be safe and viable and that basically depends on the mine opening up again.